Warming in the Baltic Sea region is expected to continue and alter the marine ecosystem

Category: Press release

27/09/2013 11:01

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A recently released report
on climate change in the Baltic Sea area looks into historical and more
recent changes in the region’s climate and changes that are projected
to take place in the future. The new assessment is an important
contribution to the 2013 HELCOM Ministerial Meeting,
to be held next Thursday in Copenhagen, Denmark. Climate is an
important controlling factor for the marine ecosystem. The report
examines possible future changes in the Baltic Sea and explains what
future climate change may mean for the protection of the sea.

The
report also contains proposals for action to counteract the expected
negative impacts from climate change on the Baltic Sea ecosystem. This
has been done to follow-up the needs for more stringent and
supplementary actions due to climate change indicated by the HELCOM 2007
and 2010 Ministerial Meetings.

Highlights from the report:

- The Baltic Sea region is warming faster than the Earth as a whole. On average since the late 19th
century the increase in annual average surface air temperature has been
0.11˚C per decade in the northern Baltic and 0.08˚C in the southern
Baltic compared to the global average of 0.05˚C per decade. The warming
is anticipated to continue.

- Annual average sea-surface water temperature has increased
by up to 1˚C per decade since 1990 and a further increase of 2 to 4˚C
is projected near the end of this century. There will be a drastic
decrease in the amount of sea-ice cover and the length of the ice season
in the Baltic Sea if the warming continues as expected.

- Precipitation during the past century has tended to increase in winter and spring
in the Baltic Sea region. Model simulations indicate that winter
precipitation could continue to increase during this century. Patterns
of river runoff tend to change considerably.

- The volume of snow in the region is expected to decrease, particularly in the southern half of the region.

- Sea-surface salinity may decrease
and the change may be largest in the region of the Danish Straits, and
small in the northern and eastern Baltic, and the smallest in the
Bothnian Bay.

- Acidification that stems from increased CO2
concentrations in the atmosphere has been slightly offset by an
increase in alkalinity; the decrease of 0.15 pH units expected for
marine systems from the increased atmospheric CO2 concentrations has been diminished by roughly 0.03 units due to increased alkalinity from the catchment area.

- Changes in ecosystem structure and functioning
are expected as a result of climate change, warming in particular. Such
changes would include shifts in the ranges of species and distribution
of habitats, as well as a decrease of oxygen in the water.

- Proposed actions to buffer the Baltic Sea ecosystem against the expected negative changes:
reduction of nutrient inputs to the maximum allowable levels, overall
reduction of human pressures stemming from activities such as shipping,
fisheries and construction activities, and lastly, the report proposes
strengthening of the network of marine protected areas so that it will
ensure a safe space for species and habitats.

The
previous assessment of climate change in the Baltic Sea Area was
released in 2007 (HELCOM BSEP No. 111) and the broader technical book,
Assessment of Climate Change for the Baltic Sea Basin, in 2008,
published by Springer. The current assessment builds on and extends the
previous assessment, and summarizes the current state of knowledge.

The report is a result of close collaboration between HELCOM and Baltic Earth, the successor programme to BALTEX.
It is based on the Second Assessment of Climate Change for the Baltic
Sea which is to be released in 2014. The material used for this
assessment has been produced by more than 120 experts from the Baltic
Sea region within the framework of BALTEX/Baltic Earth. The proposals
for action stem from the work of HELCOM.

The Baltic Marine Environment Protection Commission, usually referred to as HELCOM,
is an intergovernmental organisation of the nine Baltic Sea coastal
countries and the European Union working to protect the marine
environment of the Baltic Sea from all sources of pollution and to
ensure safety of navigation in the region. Since 1974, HELCOM has
governed the ‘Convention on the Protection of the Marine Environment of
the Baltic Sea Area’, more commonly known as the Helsinki Convention.